1. Field
Embodiments of the disclosure relate generally to cryogenic pumping systems and more particularly to embodiments for a system employing multiple thermodynamic pumping chambers sequentially receiving cryogenic liquid from a tank and interconnected though a heat exchanger to a gas supply tank for continuous gas supply.
2. Background
The use of liquid hydrogen, LH2, for higher density storage and the conversion of LH2 to gaseous hydrogen (GH2) for use in reciprocating and other internal combustion engines is a growing requirement. As an exemplary use, the need for high altitude long endurance (HALE) type Unmanned Aerial Vehicles with large reciprocating engines is growing exponentially and may soon reach 3,000 vehicles per year. Use of hydrogen for fueling these vehicles has been demonstrated as an efficient and environmentally friendly solution. However, reasonable storage densities for hydrogen can only be achieved with cryogenic storage as a liquid. Each vehicle will have a need for a LH2 hydrogen pump and GH2 conversion system. Without a suitable pump, the vehicle will not be able to meet the long endurance requirements of HALE vehicles. Reliable continuous flow of GH2 for the engine is a necessity.
Prior mechanical LH2 pumping systems supplying liquid to conventional heat exchangers for conversion to gas, such as those used in rocket fueling systems, have proved complex and insufficiently reliable for extended usage. Unlike rocket systems which deplete their fuel within a matter of seconds or minutes, applications such as HALE require continuous GH2 supply for days or longer. Additionally, reusability of the system without extraordinary refurbishment requirements is needed.
It is therefore desirable to provide and LH2 pumping system which has simplified mechanical requirements while providing continuous flow for GH2 conversion over an extended period.